This invention relates to a metal ion adsorbent and a process for preparing the same, and particularly to a metal ion adsorbent applicable to a purification system of nuclear reactor coolant, particularly suitable for purifying high temperature cooling water and a process for preparing the same.
A boiling water type nuclear reactor has a purification system for the nuclear reactor coolant for purifying cooling water in a nuclear reactor pressure vessel. The purification system of the nuclear reactor coolant has a filtration-demineralization apparatus comprising precoated powdery ion exchange resin, and further has both a regenerating heat exchanger and a non-regenerating heat exchanger. Coolant, after being cooled in individual heat exchangers, flows into the filtration-demineralization apparatus, which is back-washed with a frequency of about two weeks, generating a large amount of used powdery ion exchange resin as a radioactive waste. To reduce an amount of such radioactive waste and also to adsorb radioactive substances, it was proposed to use oxine impregnated activated charcoal. Above 150.degree. C., oxine is gradually released from the oxine impregnated activated charcoal, and the releasing is accelerated at a higher temperature, deteriorating its adsorbability, and it is impossible to use it above 150.degree. C. On the other hand, the cooling water in a nuclear reactor pressure vessel is at a temperature as high as about 280.degree. C., and thus development of a powerful oxine impregnated activated charcoal having a high adsorbability even at a higher temperature has been keenly desired.